Variable speed control for knitting machine



Jun 20, 967 M. SPINRAD ETAL VARIABLE SPEED CONTROL FOR KNITTING MACHINE5 Sheets-Sheet 1 Filed Oct. 1, 1965 INVENTQR. MHLCOM SPINRHD BY BRYCEE-HOVERTERIJR- June 20, 1967 M. SPINRAD ETAL 3,326,341

VARIABLE SPEED CONTROL FOR KNITTING MACHINE Filed Oct. 1, 1965 I)Sheets-Sheet 2 INVENTOR. MHLCOM SPm RD BY BRYCE E-HOVERTERPR.

14770/P/VEK June 20, 1967 M. SPINRAD ETAL VARIABLE SPEED CONTROL FORKNITTING MACHINE Filed Oct. 1, 1965 5 Sheets-Sheet 5 INVENTOR. MnuzomSPmRQD BY BRYCE E. HOVEFZTEROR moT United States Patent 3,326,341VARIABLE SPEED CONTROL FOR KNITTING MACHINE Malcolm Spinrad and Bryce E.Hoverter, Jr., Reading, Pa., assignors to American Safety Table Company,Inc., Reading, Pa., a corporation of Pennsylvania Filed Oct. 1, 1965,Ser. No. 492,229 Claims. (Cl. 192-18) This invention relates generallyto speed control for knitting machines, and more particularly isdirected toward speed changing for such machines by electrical controlmeans as distinguished from mechanical pulley or gear changing orhydraulic speed changing devices.

As is well known, circular knitting machines are operated at variousdifferent speeds when different portions of a stocking are for examplebeing knitted. By way of illustration, a relatively high speed may beemployed for the knitting of welt, leg and foot portions of the stockingwhile a lower speed is required for heel and toe knitting. Other speedsare also required for pattern drum moves and yarn changes. In the past,speed changing has been generally accomplished by selectively utilizingone of a plurality of different speed drive pulleys, by mechanical gearshifting in a gear control box interposed between a motor or line shaftand the knitting machine drive mechanism, by providing multi-speedelectrical motors together with somewhat elaborate electrical controlcircuitry, or by employing a fluid drive speed changing unit utilizing afluid motor and pump.

The present invention constitutes an improvement over these systems inthat the speed control mechanism is physically small, mechanically andelectrically simple, quickly and easily installable to existingequipment and readily inexpensively serviceable in the field. Briefly,the invention contemplates the use of an electrically controlledclutch-brake device operatively disposed between a substantiallyconstant speed motor or line shaft and the drive system of the knittingmachine, together with a centrifugally operated governor apparatus whichdetermines the duty cycle of the clutch device to thereby control thecoupling of the constantly running motor or line shaft to the knittingmachine drive system. Accordingly, it is a primary object of ourinvention to provide a novel apparatus for driving a rotatable shaft atany one of a number of selectable speeds from a constantly rotatinginput drive shaft by electrically controlling the mechanical couplingbetween the two shafts.

Another object of our invention is to provide a novel variable speedcontrol apparatus as aforesaid in which the output shaft is coupled tothe input shaft on a time variable basis resulting in a coupling dutycycle between 0% and 100% corresponding to an output shaft speedvariable between 0% and 100% of the input shaft speed.

A further object of our invention is to provide a novel speed controlapparatus as aforesaid wherein the coupling between output shaft andinput shaft is mechanically effected by means of electrical controlcircuitry including output shaft speed monitoring means and apparatusfor programming such monitor means in accordance with the desired outputshaft speed at different times in the operating cycle of the workutility or apparatus driven from the output shaft.

The foregoing other objects of our invention will become clear from areading of the following specification 3,326,341 Patented June 20, 1967in conjunction with an examination of the appended drawings wherein:

FIGURE 1 illustrates in end elevation a knitting machine with the speedcontrol apparatus according to the invention operatively coupledthereto;

FIGURE 2 is a vertical sectional view on an enlarged scale through theelectrically controlled clutch-brake device and speed control governorportion of the apparatus according to the invention as would be seenwhen viewed along the line 22 of FIGURE 1;

FIGURE 3 is an end view on an enlarged scale of the rotatable portion ofthe speed governor device as would be seen when viewed along the line3-3 of FIGURE 2;

FIGURE 4 is a view of the rotatable switch control portion of theapparatus shown in FIGURE 3 taken at right angles to FIGURE 3 as wouldbe seen when viewed along the lines 44 thereof;

FIGURE 5 is an exploded perspective view of the switch controlledgovernor structure, a portion of which is seen in FIGURES 3 and 4,illustrating aspects not clearly visible in the sectional view of FIGURE2; and

FIGURE 6 is a schematic electrical diagram of the entire speed controlsystem according to the invent-ion.

In the several figures, like elements are denoted by like referencecharacters.

Turning now to the drawings, consider first FIGURE 1 which illustrates aknitting machine designated generally as 10, the functioning parts ofwhich are driven from a pulley 11 by means of a drive belt 12 whichlatter extends downward and is trained about a pulley 13 driven througha gear reduction box 14 from a drive belt 15. As best seen from FIGURE2, the drive belt 15 is trained about a pulley 16 fixedly secured upon adrive shaft 17 journaled by ball bearings 18 and 19 in the cup-shapedend bell 20 which is fixedly secured as by. bolts 21 to a clutch brakehousing 22. The housing 22 is fixedly secured by bolts 23 to the frame24 of an electric motor 25 so that the drive shaft 17 is axially alignedwith butt end spaced from the shaft 26 of electric motor 25 whichextends into the clutch-brake housing 22 and has fixedly secured upon anend thereof a flywheel 27 formed with an annular cylindrical flange 28presenting toward the end bell structure 20.

Th end bell 20 is formed with a main wall 29 having a central hub 30within which are held the drive shaft ball bearing supports 18 and 19.Projecting axially toward the flywheel 27 from the main Wall 29 of theend bell 20 are a pair of concentric annular cylindrical outer and innerflanges 31 and 32 respectively, an outer annular recess 33 being definedbetween the flanges 31 and 32 and an inner annular recess 34 beingdefined between the inner flange 32 and the hub structure 30 of the endbell 20. Positioned in the base of the annular recess 33 is anelectrically energizable annular clutch coil 35, and similarlypositioned within the annular recess 34 is an electrically energizableannular brake coil 36. Fixedly secured to the inner face of the hub 30and within the inner cylindrical flange 32 is a brake shoe disk 37.

The inner end of drive shaft 17 has afiixed thereon for rotationtherewith a hub 38 upon which is disposed for axial shifting movementwith respect thereto a clutch disk 39 and a brake disk 40 providedrespectively with friction facings 41 and 42. The clutch coil 35 whenelectrical- 1y energized sets up a magnetic flux path 43 which causesthe clutch disk 39 to shift to the left on shaft hub 38 and Q engageconstantly rotating motor flywheel 27 to thereby rotate the drive shaft17 and output pulley 16. Energization of the brake coil 36 establishesthe magnetic flux path 44 which shifts brake disk 40 to the right onshaft hub 38 of drive shaft 17 so that it strongly engages the brakeshoe disk 37 to thereby brake the drive shaft 17 to a stop. The outputpulley 16 is thus driven by the electric motor 25 when the clutch coil35 is energized, and is braked to a stop whenever the brake coil 36 isenergized.

The output pulley 16 is provided with a pulley guard 45 secured to theend bell 20 as by means of the long bolt 46. Extending outward through acentral opening in the pulley guard 45 is a reduced diameter extension47 of drive shaft 17 upon the outer end of which is fixedly secured forrotation therewith the rotor 48 of a governor device for controlling thespeed of output pulleys 16. The governor rotor is engaged in an electriccircuit with the governor stator 49 which is fixedly carried by a hollowgenerally cylindrical governor housing 50 mechanically supported by arm51 secured to the pulley guard 45 and end bell 20 by bolt 46. The rotorand stator are enclosed by a hollow cylindrical cover cap 52 securableto the housing shell 50 by studs 53 extending from the housing throughthe cover cap and upon which are threaded nuts 54.

While FIGURE 2 shows the assembled organization of the governor device,detailed structural aspects of the governor are most clearly understoodby referring also to FIGURES 3, 4 and 5. As best seen in FIGURE 5, thestator 49 is formed from an annular circular disk 55 of electricalinsulating material, such as phenolic board, and is provided atdiametrically opposite edges with holes 56 through which are projectablethe studs 53 carried by the housing shell 50 so that the stator disk 55seats fiatwise against the open annular end of the housing shell 50.Fixedly carried by the stator insulator disk 55 at radially differentdistances from the center of the disk are inner, intermediate and outerelectrical brush holders 57, 58 and 59 respectively each carrying anelectrical contact brush 60. The stator insulator disk 55 and governorhousing shell 50 are centrally apertured as at 61 and 62 respectively topermit passage therethrough of the governor rotor support shaft 47 ontothe end of which is projected the rotor hub 63 secured thereon by setscrews 64.

As best seen from FIGURES 3, 4 and 5, the rotor 48 consists of a disk ofinsulating material 65 to one surface of which are fixedly securedinner, intermediate and outer conductive rings 66, 67 and 68respectively. The conductive rings are all insulated electrically fromone another and are concentric with the rotor hub 63. In the assembledgovernor device as seen in FIGURE 2, the brushes of brush holders 57, 58and 59 engage respectviely with the conductive rings 66, 67 and 68. Asbest seen from FIG- URES 3 and 4, secured to the opposite side of therotor insulator disk 65 are two pairs of contact assemblies designatedgenerally as 69 and 70. The contact assembly 69 includes a first contactarm 71 electrically connected through insulator disc 65 to conductivering 68 by metal pins 72, and a contact arm 73 electrically connected toconductive ring 67 by metal pins 74. Similarly, contact assembly 70includes a contact arm 75 electrically connected to outer conductivering 68 by pins 76, and a contact arm 77 electrically connected to innerconductive ring 66 by pins 78.

Each of the contact arms includes an intermediate resilient portionwhich allows the contact arm to flex in a direction transverse to theaxis of rotor rotation, these resiliently flexible contact arm portionsbeing designated as 71a, 73a, 75a and 77a. The arm sections 71a and 75aare somewhat more flexible than the arm sections 73a and 77a so that thecentrifugal forces developed at the free ends of the contact assemblies69 and 70 under conditions of rotor rotation cause contact arms 71 and75 to shift outward away from the rotor hub at a different rate fromthat experienced by contact arms 73 and 77. Consequently, the normallyclosed contacts at the ends of 4 contact arms 71 and 73, as well as arms75 and 77, are caused to separate when a sufficiently high rotorrotation has been developed to cause flexure of contact arm sections 71aand 75a.

Since, with the contacts of contact assembly 69 engaged with one anotherelectrical continuity is maintained between conductive rings 67 and 68of the rotor, and since this electrical continuity can be broken bycausing the contacts of contact assembly 69 to separate when the rotor48 is rotated at some particular speed, it is apparent that an externalelectrical circuit connected to the contact assembly through theconductive rings 67 and 68 can be controlled by the speed of the rotorso that circuit continuity exists below a predetermined rotor speed whenthe contact assembly is closed, and is broken above the predeterminedrotor speed when the contacts are open. Similarly, contact assembly 70functions to control an external electrical circuit connected to rotorconductive rings 66 and 67.

The particular rotor speeds at which contact assemblies 69 and 70 arecaused to open their contacts may be selectively controlled by means ofadjustment cones 79 and 80 respectively. Each of the cones 79 and 80 isexternally threaded and physically supported in a mount carried by therotor insulator disk so that the pointed end of the cone 79 bearslaterally against the contact arm 73 of contact assembly 69 while thecone 80 is similarly disposed with respect to the contact arms 77 ofcontact assembly 70. Rotation of the cones causes the contact arms 73and 77 to be shifted outward away from the rotor hub 63 and to therebyalso carry outward the contact arms 71 and 75. Such outward movement ofcontact arms 71 and 75 corresponds of course to progressively higherspeeds of rotation of the rotor 48 so that when for example contact arm71 has been mechanically outwardly shifted by cone 79 to a positionwhich it would not assume until the rotor speed had reached a certainvalue, then it follows that further outward movement of contact arm 71will not occur until the actual rotor speed exceeds such value. Thus,the cones 79 and 80 may be used to set the rotor speeds at which thecontact assemblies 69 and 70 will open.

With two contact assemblies set to open at different speeds, it is clearthat three discrete rotor speed ranges may be established, the-firstspeed range being below the break point of either contact assembly, thesecond range being above the break speed of one contact assembly butbelow that of the other, and the third range being above the break speedof the second contact assembly. Similarly, four speed ranges may beprovided with three contact assemblies, and so forth as desired.

Recalling from FIGURE 2 that the output pulley 16, and hence the drivebelt 15, is coupled to the constantly rotating motor flywheel 27 by theclutch disk 39 when the clutch coil 35 is energized, it will now beunderstood that three different rotational speeds of output pulley 16may be provided for by controlling the energization of clutch coil 35 inconjunction with the use of governor contact switch assemblies 69 and70. By way of illustration, high speed operation of the pulley at theflywheel rate is provided for by constant energization of clutch coil 35in a circuit which completely bypasses the governor device. Medium speedoperation is provided for by energization of the clutch coil 35 throughone of the contact assemblies, say contact assembly 70, at a speeddetermined by the mechanical setting of rotor control cone 80. Low speedoperation is provided for by controlling energization of the clutch coil35 through governor contact switch assembly 69 at a speed determined byrotor carried adjustment cone 79.

Assuming that the continuous flywheel speed provided by electric motor25 is approximately 1750 revolutions per minute and it is desired tooperate the knitting machine 10 at a top speed of approximately 440revolutions per minute, then the gear reducer 14 would be chosen toprovide a four to one speed reduction. Further, if the intermediate andlow speed of the knitting machine are desired to be approximately 250rpm. and 125 rpm, then intermediate speed governor contact assembly 70would be adjusted to open when the rotational speed of output pulley 16becomes 1000 rpm. while the low speed control governor contact assembly69 would be adjusted to open at an output pulley speed of 500 rpm.Substantially constant machine speed is maintained by rapid opening andclosing of the particular operative contact assembly of the governor tocause continual declutching from and reclutching to the high speed motorflywheel 27 at the rate required. This operation is automatic since arise in output pulley speed above the desired level opens the governorcontact assembly to declutch from the flywheel and permit the outputpulley speed to begin to coast downward. As soon as the output pulleyspeed drops below the contact assembly preset speed, the contactassembly recloses and again clutches the output pulley into the highspeed flywheel to increase the output speed. This cyclic operationmaintains the machine speed substantially constant at the desiredpressure value.

Refer now to FIGURE 6 which illustrates in schematic form the electricalcontrol circuitry operative to provide speed control for a device suchas the knitting machine by means of the apparatus according to theinvention as shown in FIGURES 2 through 5. Alternating electricalcurrent is 1 provided from a source of electrical energy through thetransformer 81 to the bridge rectifier 82. The positive terminal ofrectifier 82 is connected via conductor 83 to a current controllingrheostat 84 which is in turn connected via conductor 85 to one end ofclutch coil 35 and brake coil 36, each of the clutch and brake coilsbeing shunted by a reversely poled diode 86. The opposite terminal ofclutch coil 35 is connected via conductor 59a, its associated brushassembly 59 and rotor conductive ring 68 to contact arms 71 and 75 ofrotor contact assemblies 69 and 70, while also being connected viaconductor 87 to one contact 88 of a single pole double throw switchhaving a second contact 89 and pole 90. The switch contact 89 isconnected via governor brushholder conductor 57a and rotor conductivering 66 to contact arm 77 of rotor contact assembly 70. Pole 90 ofcontrol switch 91 connects via conductor 92 to one contact 93 of asecond single pole double throw control switch 94 having a secondcontact 95 and a pole 96, the second contact 95 being connected viaconductor 58a and the associated governor brush holder 58, brush 60 andconductive ring 67 to contact arm 73 of rotor contact assembly 69.

Pole 96 of control switch 94 connects via conductor 97 to a normallyclosed contact 98 of a relay 99 having three poles 100, 101 and 102,contact 98 being engaged by pole 101 when relay 99 is in its deenergizedcondition. When relay 99 is energized so that the poles thereoftransfer, pole 101 disengages from contact 98 and engages contact 103which is connected via conductor 104 to the end of brake coil 36 whichis not connected to conductor 85. Relay poles 100 and 102 are bothnormally open circuits when relay 99 is deenergized, engagingrespectively with contacts 105 and 106 when the relay becomes energizedto transfer its poles.

Relay poles 101 and 102 are electrically tied together and commonlyconnected to one side of start switch 107 via conductors 108 and 109,the other side of start switch 107 being returned to the negative sideof DC. power supply 82 through normally closed brake release switch 110and conductor 111. Relay contact 105 returns to the negative side ofrectifier 82 through pilot light 112, while relay contact 106 connectsto one side of relay coil 113 and also to one side of each of aplurality of normally open switches 114 through 117, the switches beingconnected in parallel and having their opposite terminals commonlyconnected through conductor 118 to conductor 109. The end of relay coil113 not connected to relay contact 106 is connected via conductor 119 tothe positive terminal of rectifier 82.

The clutch coil 35 and brake coil 36 are of course physically locatedinside the housing 22 shown in FIGURE 2, the contact assemblies 69 and70 are located in the governor device also shown in FIGURE 2, and thecontrol switches 91 and 94 are part of the knitting machine 10 and arecaused to transfer their poles at appropriate times during the cycle ofmachine operation to effect changes in machine speed appropriate to theparticular machine operation at that point being carried out. Typically,these control switches 91 and 94 may be actuated and deactuated bymachine controlled rotating cams. The switches 114 through 117 are alsoassociated with the knitting machine 10 and are typically cam operatedto be selectively closed when it is desired to stop the machine, forexample upon breakage of a needle or thread, when the machine is tooperate for a single cycle, or for some other stop motion function. Theswitches 107 and 110, rheostat 84, relay 99 and the power supply may beconveniently located at any desired point, which usually will be at themachine itself.

Consider now that the circuit is as indicated in FIG- URE 6 with startswitch 107 open and control switches 91 and 94 in their solid linepositions as illustrated, The knitting machine 10 is quiescent theclutch coil 35 and brake coil 36 are deenergized but the electric motor25 is energized so that flywheel 27 is rotating at its constant speed ofsubstantially 1750 revolutions per minute. Closure of start switch 107causes current to flow from rectifier 82 through conductor 83 andrheostat 84 to clutch coil 35, over conductor 87 and through controlswitches 91 and 94 to contact 98 and pole 101 of relay 99, thence overconductors 108 to 111 through switch 107 and 110 to rectifier 82.

With clutch coil 35 energized, clutch disk 39 is pulled into engagementwith flywheel 27 and output pulley 16 is driven at the full flywheelspeed corresponding to high speed operation of the knitting machine 10.With the machine operating, assume that control switch 91 is caused totransfer its pole from contact 88 to contact 89 so that energization ofclutch coil 35 can no longer occur over conductor line 87 but must takeplace via conductor 5911, contact assembly 70 of the speed governor andconductor 57a. Since contact assembly 70 is for purposes of illustrationto cause output pulley 16 to be driven at a rate of 1000 revolutions perminute, it is clear that the substantially higher flywheel rate of 1750revolutions per minute has necessarily caused the contact arms 75 and 77to disengage and prevent energization of clutch coil 35. Consequently,the clutch is disengaged and output pulley 16 immediately slows down dueto the load imposed thereon by the knitting machine 10. As soon as thepulley speed has dropped to the 1000 rpm. level, contact assembly 70closes to reenergize clutch coil 35 and control the speed of outputpulley 16 in the manner previously described.

Assuming now that it is desired to further reduce the machine speed foryet a different type of machine operation to the low speed 500 rpm.range, control switch 94 is caused to transfer its pole 96 from contact93 to contact to thereby remove control of clutch coil energization fromgovernor contact assembly 70 and transfer such control to contactassembly 69. In this manner changes in machine speed are effectedthroughout the cycle of machine operation by selectively transferringthe poles of the control switches 91 and 94.

When the machine has completed its operation, a stop motion switch suchas 114 is caused to automatically close and thereby enable current toflow from rectifier 82 through conductor 119, relay coil 113, switch 114and conductor 118 back to conductor 109 and hence to the return side ofrectifier 82. Relay 99 is thereby actuated causing poles 100, 101 and102 to respectively engage contacts 105, 103 and 106. .Disengagement ofrelay pole 101 from contact 98 breaks the circuit continuity to clutchcoil 35 to thereafter prevent any clutching operation, and engagement ofpole 101 with contact 103 energizes brake coil 36 to thereby immediatelybrake output pulley 16 to a halt. Engagement of pole 100 with contact105 lights pilot light 112 to indicate a stop condition of the machine.Engagement of relay pole 162 with contact 106 establishes a holdingcurrent circuit for relay coil 113 to maintain the relay energized underconditions where it may be desirable to utilize switches of themomentary-make type as one or more of the switches 114 through 117. Withthe machine stopped the brake coil 36 may be deenergized by opening thebrake release 110. This of course also deenergizes relay 99 andreestablishes the relay conditions illustrated in FIGURE 6.

Having now described our invention in connection with a particularlyillustrated embodiment thereof it will be appreciated that modificationsand variations of our invention may now naturally occur from time totime to those persons normally skilled in the art without departing fromthe essential scope or spirit of our invention, and accordingly it isintended to claim the same broadly as well as specifically asillustrated by the appended claims.

What is claimed to be new and useful is:

1. Speed control apparatus for controlling the operating speed of a Workutility which is is desired to drive an any of a plurality of selectabledifferent speeds from, a constant speed primary drive source, comprisingin combination,

a power transmission having a rotary input drive shaft connectable to aconstant speed drive source, a roa tary output drive shaft connectableto the work utility to drive the latter, and an electrically actuatableclutch effective when actuated for coupling the rotary outputdrive-shaft to the rotary input driveshaft, said speed control apparatuscomprising in combination,

speed selection electric switch means for selecting any one of aplurality of different speeds at which it is desired to operate a workutility, and speed sensing electric switch means connected in electriccircuit with the electrically actuatable clutch and a source of electricpower, said speed sensing switch means being operatively coupled to thepower trans-mission rotary output drive shaft for simultaneous rotationtherewith and responsive to departure of the output drive shaftrotational speed from the selected desired speed to alter the electriccircuit conditions to thereby actuate said clutch means whenever theoutput drive shaft rotational speed drops below said desired speed andto deactuate the clutch means whenever the output drive shaft rotationalspeed rises above the selected desired speed.

2. The speed control apparatus as set forth in claim 1 wherein saidspeed selection switch means further includes means for locking out ofsaid electric circuit said speed sensing switch means and simultaneouslycontinuously actuating the clutch independently of said speed sensingswitch means.

3. The speed control apparatus as set forth in claim 1 wherein saidspeed selection switch means is coupled to and automatically opera-tedby means associated with said work utiilty to thereby provide automaticprogrammed work utiilty speed selection.

4. The apparatus as set forth in claim 1 wherein the power transmissionfurther includes output drive shaft selectively actuatable brake means,and wherein said speed control apparatus further includes selectivelyoperable means coupled to the actuatable brake means effective whenoperated to actuate the brake means and quickly brake to a stop thepower transmission output drive shaft.

5. Speed control apparatus for controlling the operating speed of a workutiilty which it is desired to drive at any of a plurality of selectabledifferent speeds from a constant speed primary drive source, comprisingin combination,

C? o a power transmission having a rotary input drive shaft connectableto a constant speed drive source, a rotary output drive shaftconnectable to the work utility to drive the latter, and an electricallyactuatable clutch effective when actuated for coupling the r0- taryoutput drive-shaft to the rotary input drive-shaft, said speed controlapparatus comprising in combination,

(a) a speed control governor including a rotor and a stator, said rotorbeing mechanically couplable to the transmission output drive shaft forsimultaneous rotation therewith and including (1) speed responsiveelectric switch means having openable and closable contacts mountedlaterally of the rotor rotational axis and so oriented with respectthereto that changes in the centrifugal force exerted on said contactsdeveloped by changes in rotor rotation rate cause the state of saidswitch contacts to change between closed state and open state,

(2) adjustable means engaged with said electric switch means effectiveto set the rotor rotation rate at which said switch means contactschange state, and

(3) a plurality of separate electrically conductive rings each of whichis electrically connected to a different one of said switch contacts andconcentric with the axis of rotor rotation,

said stator being mechanically fixedly positioned adjacent to said rotorand carrying individual electrical contacts each of which iselectrically engaged with a different one of said rotor conductiverings,

(b) speed selection electric switch means connected in electric circuitthrough said stator contacts with said rotor carried speed responsiveswitch means and connectable with the electrically actuatable clutch anda source of electric power effective to selectably render said speedresponsive switch means operative and inoperative for controlling theactuation of the electrically actuatable clutch,

said speed responsive switch means when operative being effective toalter the electric circuit conditions to actuate the clutch whenever theoutput drive shaft rotational speed drops below said selected speed andbeing effective to deactuate the clutch whenever the output drive shaftrotational speed rises above the selected speed.

6. The apparatus as set forth in claim 5 wherein said rotor carriedspeed responsive electric switch means includes at least two independentswitches and wherein said adjustable means engaged therewith includesmeans for independently setting the rotor rotation rates at which thecontacts of each rotor switch change state.

7. The apparatus as set forth in claim 5 wherein said rotor carriedspeed responsive electric switch means includes at least two independentswitches and wherein said adjustable means engaged therewith includesmeans for independently setting the rotor rotation rates at which thecontacts of each rotor switch change state, and wherein said speedselection switch means is coupled to and automatically operated by meansassociated with said work utility to thereby provide automaticprogrammed work utility speed selection.

8. The apparatus as set forth in claim 5 wherein said speed selectionswitch means renders the clutch continuously actuated Whenever saidspeed responsive switch means is rendered inoperative by said speedselection switch means.

9. The apparatus as set forth in claim 5 wherein the power transmissionalso includes output drive shaft selectively actuatable brake means, andwherein said apparatus further includes selectively operable controlmeans coupled to the actuatable brake means effective when operated toactuate the brake to quickly brake to a stop the output drive shaft.

10. The apparatus as set forth in claim 5 wherein the power transmissionalso includes an output drive shaft selectively electrically actuatablebrake, and wherein said apparatus further includes selectively operablecontrol means in electric circuit with the electrically actuatable brakeand clutch effective when operated to actuate the brake and deactuatethe clutch to quickly brake to a stop said output drive shaft.

References Cited UNITED STATES PATENTS Grifiin 192-103X Edwards 192-18.2Neal 200-80 Shepard 192-l8.2 Myers 192-18.2X Schwartz et a1. 200-80 MARKNEWMAN, Primary Examiner.

ARTHUR T. MCKEON, Examiner.

Disclaimer 3,326,341.-Mal00m Spinmd and Bryce E. Hoverter, J12, ReadingPa. VARI- ABLE SPEED CONTROL FOR KNITTING MACHINE. Patent dated June 20,1967. Disclaimer filed May 28, 1969, by the assignee, American SafetyTable Company, Inc. Hereby enters this disclaimer to claims 1, 2, 4, 5,6, 8, 9 and 10 of said patent.

[Oyficz'al Gazette October 14, 1.969.]

1. SPEED CONTROL APPARATUS FOR CONTROLLING THE OPERATING SPEED OF A WORKUTILITY WHICH IS IS DESIRED TO DRIVE AN ANY OF A PLURALITY OF SELECTABLEDIFFERENT SPEEDS FROM A CONSTANT SPEED PRIMARY DRIVE SOURCE, COMPRISINGIN COMBINATION, A POWER TRANSMISSION HAVING A ROTARY INPUT DRIVE SHAFTCONNECTABLE TO A CONSTANT SPEED DRIVE SOURCE, A ROTARY OUTPUT DRIVESHAFT CONNECTABLE TO THE WORK UTILITY TO DRIVE THE LATTER, AND ANELECTRICALLY ACTUATABLE CLUTCH EFFECTIVE WHEN ACTUATED FOR COUPLING THEROTARY OUTPUT DRIVE-SHAFT TO THE ROTARY INPUT DRIVESHAFT, SAID SPEEDCONTROL APPARATUS COMPRISING IN COMBINATION, SPEED SELECTION ELECTRICSWITCH MEANS FOR SELECTING ANY ONE OF A PLURALITY OF DIFFERENT SPEEDS ATWHICH IT IS DESIRED TO OPERATE A WORK UTILITY, AND SPEED SENSINGELECTRIC SWITCH MEANS CONNECTED IN ELECTRIC CIRCUIT WITH THEELECTRICALLY ACTUATABLE CLUTCH AND A SOURCE OF ELECTRIC POWER, SAIDSPEED SENSING SWITCH MEANS BEING OPERATIVELY COUPLED TO THE POWERTRANSMISSION ROTARY OUTPUT DRIVE SHAFT FOR SIMULTANEOUS ROTATIONTHEREWITH AND RESPONSIVE TO DEPARTURE OF THE OUTPUT DRIVE SHAFTROTATIONAL SPEED FROM THE SELECTED DESIRED SPEED TO ALTER THE ELECTRICCIRCUIT CONDITIONS TO THEREBY ACTUATE SAID CLUTCH MEANS WHENEVER THEOUTPUT DRIVE SHAFT ROTATIONAL SPEED DROPS BELOW SAID DESIRED SPEED ANDTO DEACTUATE THE CLUTCH MEANS WHENEVER THE OUTPUT DRIVE SHAFT ROTATIONALSPEED RISES ABOVE THE SELECTED DESIRED SPEED.